This invention relates to refractories which contain an organic binder and metal powder of low melting point in the composition thereof in addition to a conventional refractory inorganic material and which is prepared by burning the refractory composition in the temperature range of 100.degree. C. to below 800.degree. C. to thereby achieve energy saving in the production of such refractories.
In the past, bricks produced by burning the brick composition in the temperature range of 1300.degree. C. to 1800.degree. C. have been generally employed as refractory bricks. However, from the view point of energy saving and cost reduction in the production of such refractory bricks partly, unburnt bricks containing an inorganic or organic binder in the composition thereof as well as the other brick components have been employed as linings on a limited area of the inner surface of a steel refining furnace. However, the use of such unburnt bricks containing the inorganic or organic binder on the steel refining furnace presents several problems as will be described hereinbelow.
When the inorganic binder is employed in the composition of unburnt bricks adapted to be used on a steel refining furnace, the binder will possibly tend to become a source of impurities which adversely affect the quality of a steel to be produced in the furnace and furthermore, the binder in the brick composition tends to reduce the refractoriness of the brick and in consequence, the brick is easily damaged by the molten steel charge and the slag generated in the refining operation in the furnace.
When the organic binder is employed in the composition of nonburnt bricks adapted to be used on a steel refining furnace, the binder decomposes by oxidation under high temperature condition present in the furnace in operation and loses the bonding power called for the binder resulting in substantial reduction of the strength and deterioration of the brick. Therefore, the brick wears away on the side thereof facing the furnace charge and decreases strength by oxidation on the side thereof opposite from the charge facing side.
Therefore, the prior art nonburnt bricks have been employed at limited areas of a structure which is to be lined by the bricks where the bricks are employed under not severe conditions and specific steels are refined under specific furnace operation conditions.